Hydraulic press.



UNITED STATES Patented June "r, 1904.

PATENT OFFICE.

EDWARD CROIVE, OF SHEFFIELD, ENGLAND, ASSIGNOR OF ONE-HALF TO DAVY BROS., LIMITED, OF SHEFFIELD, ENGLAND, A CORPORATION.

HYDRAULIC PRESS.

SPECIFICATION forming part of Letters Patent No. 762,149, dated June 7, 1904.

Application filed June 15, 1903. Serial No. 161,538. (No model.)

To ll/ZZ whom it may concern:

Beit known that I, EDWARD CRowE, engineer and chief draftsman, a subject of the King of Great Britain, residing at Birchholm, Bushey Wood, Totley Rise, Slieflelcl,England have invented certain new and useful'Im-` provements in Hydraulic Presses, of which the following is a specification.

This invention relates to hydraulic presses for forging and for other purposes-such, for

example, as bending and testing armor-plates,

the speed of workingand the efIiciency of they press. This end is attainedmainly by the provision of means whereby the idle descent of the press-head onto its work may be effected quickly and by gravity alone and whereby the power of the pumps is caused to come into action automatically immediately the tool carried by the press-head encounters the work.

The invention will be described with reference to the accompanying drawing, which shows in an elementary form the improved apparatus and arrangement of parts, the two portions of the figure being drawn to different scales.

The press comprises a main cylinder A and ram B (one or more) for imparting the working stroke tothe press-head, and lifting-cylinders C and pistons D for imparting the return stroke, the pipe connections with these cylinders being controlled by valves arranged to operate in such manner that during the idle descent of the press-head the main and lifting cylinders can be'connected at the same time with the exhaust-tank or with each other and the exhaust in such manner as to allow the I lifting-cylinders to exhaust into and the main cylinder to draw from the exhaust-tank, so that the press-head will be permitted to descend freely by its own weight, the main pumps then eitherfrunning light or being out of work, while during the working portion of the press-stroke pressure can be supplied to the main cylinder and exhausted from the lifting-,cylinders and on the return stroke can be supplied to the lifting-cylinders and exhausted from the main cylinder alternatively.

Between the main cylinder A and the exhaust-valve Fthere is provided a self-closing .by-pass suction-valve G, which while permitfrom the main cylinder is under the control of an exhaust-valve F. The connection of the lifting-cylinders O with the main cylinder A for the passage of water from the one to the other during the descent of the main ram is also under the control of the high-pressure distribution-valve E, while the connection of the main cylinder A with the exhaust for the admission of water to the main cylinder during the idle part of the descent of the presshead is through a by-pass controlled by the self-closing suction-valve G, which permits of How in one direction only when the exhaustvalve F is closed. 8o

The upper end of the main cylinder is connected by a pipe a with the valve-box of the valves G and F and is also connected through a constantly-open annular passagef around the latter valve with a pipe c, controlled by the pump-pressure distribution-valve E. The delivery-pipe p from the pumps P connects through a constantly-open annular passage e' around valve E with a pipe o. connected by branch pipes c with the lower ends of the lifting-cylinders C.

J is the exhaust to the tank.

The hi gli-pressure distribution-valve E and the exhaust-valve F are operated by an auxiliary hydraulic-pressure service controlled by a slide-valve I-I, operated by a handing-lever, the valve H working in a valve-chest in connection with the auxiliary-pressure service in such manner that the pressure may be admitted to act alternatively on the upper end of valve E or Valve F (for the purpose of closing the one or other of those valves) or may be released therefrom. The valve H controls ports, of which two are respectively connected by pipes ezf with cylinders eff, in which the upper ends of the valves E F (which are of larger diameters than the valves themselves) work as plungers, while the third port is connected to an exhaust. It is to be distinctly understood, however, that neither this method of working these valves nor their particular construction is essential, as the valves may be adapted to be worked by steam or other power and in small presses would preferably be worked by hand, the essential features being the cooperation of the self-closing by-pass suction-valve with the exhaust-Valve and the further cooperation with those valves of a Valve controlling the distribution of the pumppressure to the main and lifting' cylinders and likewise the connection of the lifting-cylinders with the main cylinder of a press in which the lifting-cylinders are supplied by the same pumps as the main cylinder.

The action (assuming thehigh-pressure and exhaust valves to be operated by hydraulic, steam, or other Huid-pressure) is as follows: In order to lower the press-head, the valve H is moved to such position that the auxiliary hydraulic, steam, or other fluid-pressure will be admitted through pipe F2 to act on and close the exhaust valve F and will at the same time be exhausted from pipe e2. The high-pressure distribution-valve E will thereupon be caused to open by the pressure of the water coming from the lifting-cylinders and acting on the area of the valve corresponding to the difference of its two diameters. The press-head will then descend by its own weight, forcing the water out of the lifting-cylinders C throughthe pipe e, passage f' around valve F, and pipe a into the main press-cylinder A, the further quantity of water necessary to lill that cylinder being drawn from the exhaust J through the bypass suction-valve G, which is loaded by a spring g. On the tool carried by the presshead meeting the work the valve Gr will immediately close and the further motion of the press-head will be due to the action of the pumps and will be continued under the pumppressure without pause if (as would usually be the case) the pumps work continuously or are started before the tool encounters the work, the pumps in either case running light until the moment when the free descentl of the press-head is checked. To lift the presshead, the position of the valve H is reversed, auxiliary pressure being thus admitted above the high-pressure distribution-valve E, which is thereby closed to its seat, while the exhaust-valve F is caused (by the pressure acting on the area of that valve corresponding to the difference of its two diameters) to open, whereupon the water from the pumps will flow through passage e and pipe c into the lifting-cylinders C and raise the press-head, while the water from the main press-cylinderA passes out through the exhaust-valve F.

rlhe pumping-engines may be of the continuous-running type and may be fitted with a liy-wheel and centrifugal governors; but it is preferred (with a view both to the better control of the press and to economy of power) to employ pumps which are furnished with a throttle valve or its equivalent under the control of a handing-lever in order that the pumps may be started and stopped instantly at will.

I claiml. In a downwardly-acting hydraulic press wherein the main press-ram is free to descend by gravitation during the idle part of its working stroke, the combination with a positively-operated valve adapted to control the passage of water from the main press-cylinder to the exhaust and when closed, to permit the passage of water fr'om the pumps to the main press-cylinder, of an independent self-closing suction-valve on a by-pass to the said exhaust-valve, adapted to be held open by the flow of water from the exhaust to the main press-cylinder while the exhaust-valve is closed during the idle part of the descent of the main press-ram and to automatically close and thus enable the pump-pressure to come into action upon the main press-ram immediately the flow from the exhaust to the main press-cylinder ceases in consequence of the idle descent of the main press-ram being arrested, substantially as specified.

2. In ahydraulic press having main pressure and lifting rams connected with the press-head, the combination of a self-closing by-pass suction-valve and a positively-operated exhaustvalve interposed between the main press-cylinder and the exhaust, adapted the one to permit flow of water from the exhaust to the main cylinder, while the other is closed during the idle descent of the press-head, and of a pump-pressure distribution-valve controlling the delivery of the pumps, the said valve also controlling communicationbetween the main and lifting cylinders, substantially as specified.

3. In a hydraulic press having main pressure and lifting rams connected with the press-head, the combination of a self-closing by-pass suction-valve and a positively-operated exhaust- Valve interposed between the main press-cylinder and the exhaust, adapted the one to permit flow of water from the exhaust to the main cylinder, while the other is closed during the idle descent of the press-head, a pumppressure distribution-valve controlling the delivery of the pumps, the said Valve also controlling communication between the main and lifting' cylinders, the exhaust-Valve and the IOO pump-pressure distribution-valve being both carried by pistons adapted to Work in cylinders, and a hand-operated slide-valve adapted to control the supply of'auxiliary or independent pressure to the one and its exhaust from the other of the said valve-operating cylinders alternatively, substantially as described. v

4. In a hydraulic press wherein both the main press and lifting cylinders are supplied from a single source of high pressure, the combination with valves adapted the one to control the passage or' Water from the main presscylinder to the exhaust, and the other to distribute the supply of high pressure to the main and lifting cylinders alternatively, of means for enabling said valves to be opened by the action of the high pressure andclosed by the action of auxiliary pressure from an independent source of supply in alternation with one another, said means consisting of pistons integral with the respective valves and litted to Work each in a cylinder wherein the piston presents a certain area to the high pressure tending to open the valve and an effectively superior area to the auxiliary pressure tendingto close the valve, and a hand-operated valve adapted to control the distribution of the said auxiliary pressure to, and its exhaustion from the respective valve cylinders alternatively, substantially as described.

ED WARD CROVE.

Witnesses:

BAIN L. CAMPBELL, W. H. SLATER. 

